The following is a list of Lieutenant Governors of Ontario and governors of predecessor colonies. Though the present day office of the lieutenant governor in Ontario came into being only upon the province's entry into Canadian Confederation in 1867, the post is a continuation from the first governorship of Upper Canada in 1791, which itself branched out of the governorship of the Province of Quebec. From 1841 to 1867, the Governors General of the Province of Canada simultaneously acted as the direct governor of Canada West (what is present day Ontario), only occasionally appointing a lieutenant to act in their stead.
Prior to 1868 vice-regals were active or previous members of the British Army, but after Stisted the office was not held by non-Canadians or British military officers (Gzowski was a former Imperial Russian officer but was an engineer in Canada when serving as acting vice-regal).